According to the concept of ophiolite in 1 970s，exposure of marie—ultramafic rocks in the orogenic zone hasbeen interpreted to represent the relic of fossil ocean lithosphere based on its lithology units consisting withoceanic crust and upper mantle．So the ophiolite is a key e．vidence of boundary between the fossil plates，and hasbeen played an im portant role on the formulation and advancement of the plate tectonic theory． Recently，ophiolite is divided into M OR—and SSZ—types based on the formation tectonic setting． M OR-type ophioliteformed at Mid—ocean ridges(M oR)，and SSZ—type ophiolite formed on the supra—subduction zone caused bythe ocean—continent subduction or intra—ocean subduction．and there are obvious difference in mantle sequence，cumulated assem blage and lavas in petrology， mineralogy and geochemistry between M OR— and SSZ—typeophiolites．This classification explains well the various ophiolites and the difference between the ophiolite andoceanic lithosphere．During the subduction of oceanic lithosphere，the M OR—type ophiolite was subducted，or ispreserved only as dismembered thrust sheets or blocks in ophiolitic m61ange，while SSZ—type ophiolite，asfragments of modified oceanic or rebirth lithosphere caused by fossil oceanic plate subduction，is commonlypreserved in the orogenic zone due to it formed above subduction zone．Therefore，SSZ-type ophiolite is majorone preserved well in the orogenic zone．Also discussed in this paper are the problems in the ophiolite study，such as the difference between the ophiolite and ocean lithosphere in peridotites．and the methods to solve theseproblems． And the pre—Rodinia super—continent ophiolite record is still considered poorly understanding，andwhether Archean greenstone is ophiolite or not．These are all questions to answer．